On 20.02.20 07:31, Jun Li wrote: >> -----Original Message----- >> From: Martin Kepplinger <martin.kepplinger@xxxxxxx> >> Sent: 2020年2月20日 1:37 >> To: Jun Li <jun.li@xxxxxxx>; Peter Chen <peter.chen@xxxxxxx>; >> mathias.nyman@xxxxxxxxx >> Cc: linux-usb@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Anson Huang >> <anson.huang@xxxxxxx>; shawnguo@xxxxxxxxxx; kernel@xxxxxxxxxxxxxx >> Subject: [PATCH] usb: host: xhci-plat: add XHCI_MISSING_CAS quirk >> >> From: Li Jun <jun.li@xxxxxxx> >> >> i.MX8MQ USB3 host needs XHCI_MISSING_CAS quirk to warm reset the port to enum the >> USB3 device plugged in while system sleep, as the port state is stuck in polling >> mode after resume. >> >> Signed-off-by: Li Jun <jun.li@xxxxxxx> >> Acked-by: Peter Chen <peter.chen@xxxxxxx> >> --- >> >> Hi, >> >> Because resume from S3 suspend is broken for me on imx8mq, I stumbled upon this >> patch in NXP's linux tree. (Please note that I'm not the author and I've not yet >> put my SoB tag under it). This is just a >> question: >> >> This patch (and the docs) clearly is missing in mainline Linux because the imx8mq >> devicetree description includes it (which does nothing now). >> >> I've tested this and this particular addition doesn't fix my problem: >> >> [ 84.257538] imx8mq-usb-phy 381f0040.usb-phy: bus resume >> [ 84.263195] imx8mq-usb-phy 382f0040.usb-phy: bus resume >> [ 84.268898] dwc3 38100000.usb: driver resume >> >> during resume from S3 suspend, here it still hangs. > > Is your problem a system hang? If yes, this may another issue, > where the hang happens? dwc3_resume_common()? exactly! I followed to the point it hangs once again and it's dwc3_core_init() called from dwc3_resume_common()'s "OTG" case. Specifically, dwc3_writel() is what I don't get past: https://elixir.bootlin.com/linux/v5.6-rc2/source/drivers/usb/dwc3/core.c#L934 do you have an idea why this writel() hangs? > > The question patch is to give a warm reset for connected USB > device if the link state is not connect/CAS after system resume, > otherwise host will wait 2s for device appear: > > [ 44.834831] usb 2-1: Waited 2000ms for CONNECT > ... > [ 45.055718] PM: resume devices took 3.132 seconds > > I will post this patch and doc(to be updated) to upstream later. > ok, good, thanks, martin
